DIY BT Manifold for a 2.1 Stroker

[grahams81]

Hi everyone, i bought a 2001 Leon Cupra a couple of weeks ago with a knackered auq engine (broken piston ring or holed piston) with the intention of building a fast road / track car.

I'm currently in the process of sourcing parts to rebuild the engine, so far i've got -

IE BYOC 2.1 Stroker Kit - IE Rods & JE Pistons
Second Hand (ebay) TDI Crank
AGU Large Port Head (ebay)
Calico Coated Rod / Main Bearings
ARP Main Stud Kit / Head Stud Kit / Damper Bolt
Supertech Intake / Inconel Exhaust Valves
New Supertech Valve Guides
Overbore Head Gasket Kit

Now i've got most of the bits to build a bullit proof bottom end i'm starting to look for the turbo / intake manifold bits etc.

I'm looking for around 400-450bhp so thinking about a gt3071 or maybe 3076.

Having been doing loads of research into BT kits / parts i'm really shocked by the prices of good (non ebay) tubular manifolds, i know theres loads of testing etc that goes into these designs but i'm sure there's savings to be made by somebodys who's willing to do a bit of graft & homework.

So far ive found a site in the US who sell collectors / flanges (http://www.theturboshop.com/shop.php?main_page=product_info&cPath=11_2&products_id=7) i'm planning to use butt-weld stainless bends / straights to create the bends etc.

As i work as an engineer in the dairy business i know loads of top quality Dairy pipe welders who could weld up my final incarnation but before i start i need to pick so good brains.

Does anybody know what's the optimium size to make the piping ?? or have any tips etc ??

Thanks in Advance,
Graham

 

[Seatmann]

Don't know if this helps for exhaust.

http://www.tdiclub.com/TDIFAQ/TDiFAQ-6.html#e6

http://www.myturbodiesel.com/1000q/turbocharging.htm#turboexhaust

 

[grahams81]

Cheers Seatmann,
It's quite an interesting read, there's some good points in there about Variable Vane Turbos etc like the 911's use...... anybody used one on a 1.8T ????

 

[tashacupra]

but i'm sure there's savings to be made by somebodys who's willing to do a bit of graft & homework.

Does anybody know what's the optimium size to make the piping ?? or have any tips etc ??

Thanks in Advance,
Graham

Hi, there is indeed savings to be had if you can diy your manifold, mine cost me £200 tops
With regard to tube size 1.5" nominal bore, SCH10s fitting seem to work well, the wall thickness is thick enough to handle the heat and the bore sufficient to maintain good flow.
I used a spare head as a jig and took extensive measurements from the car before I started and made a scale drawing of what I had in mind to check things would work etc, the manifold was then trial fitted in the car before final welding/machining.

 

[grahams81]

Hi Tasha,
Thanks for the information, thats really spured me on to get cracking. I've bought a large port head for the conversion so i will use the standard one as a jig.
i've read your manifold build thread - really good looks brilliant, i don't suppose you still have drawings you produced for the flanges to be cut ???
Thanks Again,
Graham.

 

[tashacupra]

Hi Graham, due to the odd ball turbo I'm using there was very little info to use for the flanges (however the garrett series flange dimensions are widely available on the net) they were done the good old-fashioned way of getting a pen and drawing round the flange, the hole's etc were then marked on to the template and that was then transferred to the plate and cut buy hand. The same applied to the head flange I just used a gasket and took measurements from the head and used dividers to replicate the pcd's for each runner.

[/IMG]
Example of template for turbo.

As for working the runners out i produced a scale bird's eye drawing of what I had in mind and then checked that against the measurement taken from the car before the fab work started, this also allowed me to work out angles etc so done away with the "cut try fit, cut again try fit, trim a little more try fit, etc."

[/IMG]
The drawing for the runners.

[/IMG]
The drawing used to work out collector angles.

Hope that helps a little, oh and sorry for the pic quality there only from an iPhone.